The present invention relates to an image capturing system and an electronic endoscope system.
Recently, an endoscope device (a spectroscopic endoscope device) equipped with a function to capture spectral images has been proposed. With such an spectroscopic endoscope device, it may be possible to obtain image information containing spectral property (e.g. a reflectivity spectrum) of a living tissue such as a mucous membrane in a digestive organ. It is known that the reflectivity spectrum of a living tissue reflects information concerning types or densities of components contained in the vicinity of a surface layer of the subject living tissue targeted for measurement. Specifically, it is known that absorbance calculated from the reflectivity spectrum of the living tissue can be obtained by linearly superimposing absorbance of a plurality of substances which constitute the living tissue.
It is known that a living tissue in a diseased portion is different from a living tissue in a healthy portion in regard to a composition and component amounts. It is reported in prior research that abnormality of a diseased portion, represented by a cancer, is deeply related to a state of blood, namely, a state of whole blood volume and oxygen saturation. It is a frequently used manner in spectroscopic analytical chemistry to qualitatively and quantitatively analyze interesting two living tissues using spectroscopically characteristic amounts of the two living tissues in the visible light region. Therefore, it is possible to estimate whether or not a living tissue contains a diseased portion by comparing a spectral property of blood of a living tissue containing a diseased portion with a spectral property of blood of a living tissue containing only a healthy portion.
The spectral images are constituted by a plurality of image information captured with light having different wavelengths. As the wavelength information contained in the spectral image (the numbers of wavelengths used to obtained image information) increases, obtained information concerning the living tissue becomes more accurate. Japanese Patent Provisional Publication No. 2012-245223A (hereafter, referred to as patent document 1) discloses an example of a spectroscopic endoscope device which obtains spectral images at intervals of wavelength of 5 nm within a wavelength region of 400 nm to 800 nm.